How to check the board HW if the jtag is not working

[hzy199411]

I have one innova2 flex board, when I use the innova2_flex_app enable the jtag access, but actually the jtag scan is failed.

open_hw_target
INFO: [Labtoolstcl 44-466] Opening hw_target localhost:3121/xilinx_tcf/Digilent/C30593ECABCD
ERROR: [Labtools 27-2269] No devices detected on target localhost:3121/xilinx_tcf/Digilent/C30593ECABCD.
Check cable connectivity and that the target board is powered up then
use the disconnect_hw_server and connect_hw_server to re-register this hardware target.
ERROR: [Common 17-39] 'open_hw_target' failed due to earlier errors.

so I suspect there maybe some HW broken.

I found here is a case that U41 and U49 component may cause the jtag not works in https://github.com/mwrnd/innova2_flex_xcku15p_notes/tree/main/debug_notes#debug-jtag-components

can you please help share more detail about the U41 and U49? I measured the voltage information are:	U41	Voltage	Diode Mode Value
PIN D	1.18V	443
PIN G	0V	466
PIN S	0V	406

U49	Voltage	Diode Mode Value
PIN D	3.3V	553
PIN G	0V	462
PIN S	0V	0

is the voltage and Diode mode value correct?

and can you please share a clear bottom picture for reference, I want to check is there some component missed.

[mwrnd]

I am reading the same voltages on a powered up (in-system) board with no JTAG connected.

Please confirm your JTAG runs at 1.8V and works with Xilinx parts. If possible, please test your JTAG on a known-working Xilinx FPGA board.

so I suspect there maybe some HW broken.

When you power up your system, which LEDs on the Innova-2 are on?

I use the innova2_flex_app enable the jtag access

Is your CX-5 firmware the newest? Please post the output of innova2_flex_app.

On a not powered, (unplugged, out-of-system) board with a multimeter in Diode Mode:

I measured the transistors:

The following are my measurements:

please share a clear bottom picture for reference

https://github.com/mwrnd/innova2_flex_xcku15p_notes/blob/main/img/Innova-2_Flex_8GB_XCKU15P_MT27808_MNV303212A-ADLT_Back.jpg https://github.com/mwrnd/innova2_flex_xcku15p_notes/blob/main/img/Innova-2_Flex_4GB_XCKU15P_MT27808_MNV303212A-ADIT_Back.jpg https://github.com/mwrnd/innova2_flex_xcku15p_notes/blob/main/img/ADLT_vs_ADIT_Back-of-PCB_Comparison.jpg

[hzy199411]

@mwrnd Thanks for your information, today I found the reason is that my board can only support to using the jtag at 12MHz. if I reduce the clock setting to 10M using the JtagSmt2 or use the 12M if using the DLC10 cable.

update some information about why I try to reduce the clock. first I use the "djtagcfg init -d JtagSmt2" to detect the jtag and it can found the jtag ID but it report unknown device:

$ djtgcfg init -d JtagSmt2
Initializing scan chain...
Found Device ID: 14a56093

Found 1 device(s):
    Device 0: UNKNOWN

then I measured the jtag waveform when run the command and confirmed the waveform result is good. (the UNKNOWN device maybe that the digilent adept utilities don't support the KU+ devices).

but when I measured the jtag waveform when open Vivado HW manager and the waveform report many 0xFF 0xFE error data. I compared the clock setting and found the clock frequency is higher than the case using "djtagcfg init -d JtagSmt2" command. so I suspect the clock maybe too fast, then I decrease the clock to 10M and found that the jtag is detect.

can you help check is your board support to use higher jtag clk frequency such as 15M? I want to confirm that the 15M jtag clock not working issue only happens on my board or other boards.

[mwrnd]

Kintex UltraScale+ devices have a lower maximum internal JTAG frequency than other UltraScale+ devices and this may be the reason behind the slower JTAG clock.

I have been running my JTAG at 6MHz and it works reliably.